Encyclopedia Astronautica
Mars Expedition NASA Lewis 1960



zmlew60.jpg
Mars NASA Lewis 1960
Faget Mars Expedition
Credit: © Mark Wade
American manned Mars expedition. Study 1960. The first NASA study of a manned Mars expedition outlined an opposition-class, nuclear thermal rocket powered spacecraft that would take seven astronauts to the planet's surface for 40 days.

Radiation protection of the crew was a major concern.

In 1960 NASA's Lewis Research Center conducted the first NASA studies of the spacecraft and equipment required for a manned expedition to Mars. A standard mission profile was established. This basically followed the Von Braun scheme of 1952. A spacecraft would be assembled in low earth orbit, and then launch itself toward Mars. After using rockets to brake into Mars orbit, a separate lander would descend from a mother ship to the surface. After exploration of the terrain it would launch itself back into Mars orbit to rendezvous and dock with the mother ship. A rocket would boost the mother ship back toward earth. The scheme differed from Von Braun's in having seven crew and using nuclear thermal propulsion, which in turn allowed a faster 420 day opposition-class mission with 40 days on Mars. Instead of using rockets to brake into earth orbit on return, an earth return vehicle would separate from the mother ship. This was seen as a 13.6 metric ton delta-wing spaceplane with a 6.7 m wingspan, which would re-enter the earth's atmosphere. The mother ship would be disposed of, sailing past earth into solar orbit. Launch date would be 19 May 1971, and total mission delta-V would be 19.8 km/s.

The danger of radiation outside the earth's protecting radiation belts was understood now, and Lewis considered provision of an appropriate radiation shelter a major driver in any expedition design. The mother ship habitation quarters provided 35 square meters of floor space on two levels, with a cylindrical radiation vault at the centerline, which doubled as sleeping quarters. Such a shelter would weigh 21.4 metric tons if a maximum exposure of 100 REM was considered permissible and no major solar flares occurred. However if the crew exposure had to be limited to 100 REM and it was assumed one flare would occur, the shelter's mass would increase to 74.5 metric tons. If crew exposure was limited to 50 REM, the mass of the shelter shot up to 127 metric tons. Lewis found that shorter duration trips were no heavier than longer trips to Mars, since the shelter would be lighter on a shorter trip for the same radiation dose. All things considered, the final Lewis conclusion that a ship using nuclear thermal propulsion, meeting the mission profile, and limiting the crewmember's dose to 100 REM, would have a total mass of 614 metric tons on departure from earth orbit.

Mars Expedition NASA Lewis 1960 Mission Summary:

  • Summary: First NASA Mars expedition design; first to propose use of nuclear thermal propulsion
  • Propulsion: Nuclear thermal
  • Braking at Mars: propulsive
  • Mission Type: opposition
  • Split or All-Up: all up
  • ISRU: no ISRU
  • Launch Year: 1971
  • Crew: 6
  • Mars Surface payload-metric tons: 40
  • Outbound time-days: 150
  • Mars Stay Time-days: 40
  • Return Time-days: 240
  • Total Mission Time-days: 420
  • Total Payload Required in Low Earth Orbit-metric tons: 614
  • Mass per crew-metric tons: 102
  • Launch Vehicle Payload to LEO-metric tons: 100
  • Number of Launches Required to Assemble Payload in Low Earth Orbit: 7
  • Launch Vehicle: Saturn V

Characteristics

Crew Size: 7.

Gross mass: 614,000 kg (1,353,000 lb).

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Associated Countries
See also
  • Mars Expeditions Since Wernher von Braun first sketched out his Marsprojekt in 1946, a succession of designs and mission profiles were seriously studied in the United States and the Soviet Union. By the late 1960's Von Braun had come to favour nuclear thermal rocket powered expeditions, while his Soviet counterpart Korolev decided that nuclear electric propulsion was the way to go. All such work stopped in both countries in the 1970's, after the cancellation of the Apollo program in the United States and the N1 booster in the Soviet Union. More...

Associated Manufacturers and Agencies
Associated Propellants
  • Nuclear/LH2 Nuclear thermal engines use the heat of a nuclear reactor to heat a propellant. Although early Russian designs used ammonia or alcohol as propellant, the ideal working fluid for space applications is the liquid form of the lightest element, hydrogen. Nuclear engines would have twice the performance of conventional chemical rocket engines. Although successfully ground-tested in both Russia and America, they have never been flown due primarily to environmental and safety concerns. Liquid hydrogen was identified by all the leading rocket visionaries as the theoretically ideal rocket fuel. It had big drawbacks, however - it was highly cryogenic, and it had a very low density, making for large tanks. The United States mastered hydrogen technology for the highly classified Lockheed CL-400 Suntan reconnaissance aircraft in the mid-1950's. The technology was transferred to the Centaur rocket stage program, and by the mid-1960's the United States was flying the Centaur and Saturn upper stages using the fuel. It was adopted for the core of the space shuttle, and Centaur stages still fly today. More...

Bibliography
  • Portree, David S. F., Humans to Mars: Fifty Years of Mission Planning, 1950 - 2000, NASA Monographs in Aerospace History Series, Number 21, February 2001.

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